High-resolution micro-Doppler imaging during neurosurgical resection of an arteriovenous malformation: illustrative case.

OBJECTIVE: Given the high-risk nature of arteriovenous malformation (AVM) resections, accurate pre- and intraoperative imaging of the vascular morphology is a crucial component that may contribute to successful surgical results. Surprisingly, current gold standard imaging techniques for surgical guidance of AVM resections are mostly preoperative, lacking the necessary flexibility to cater to intraoperative changes. Micro-Doppler imaging is a unique high-resolution technique relying on high frame rate ultrasound and subsequent Doppler processing of microvascular hemodynamics. In this paper the authors report the first application of intraoperative, coregistered magnetic resonance/computed tomograpy, micro-Doppler imaging during the neurosurgical resection of an AVM in the parietal lobe. OBSERVATIONS: The authors applied intraoperative two-dimensional and three-dimensional (3D) micro-Doppler imaging during resection and were able to identify key anatomical features including draining veins, supplying arteries and microvasculature in the nidus itself. Compared to the corresponding preoperative 3D-digital subtraction angiography (DSA) image, the micro-Doppler images could delineate vascular structures and visualize hemodynamics with higher, submillimeter scale detail, even at significant depths (>5 cm). Additionally, micro-Doppler imaging revealed unique microvascular morphology of surrounding healthy vasculature. LESSONS: The authors conclude that micro-Doppler imaging in its current form has clear potential as an intraoperative counterpart to preoperative contrast-dependent DSA, and the microvascular details it provides could build new ground to further study cerebrovascular pathophysiology.

Medical attention seeking by suspected stroke patients: Emergency medical services or general practitioner?

OBJECTIVE: Awareness campaigns advise the public to call emergency medical services (EMS) directly in case of suspected stroke. We aimed to explore patient and notification characteristics that influence direct EMS notification, the time to alert, and the time to treatment. METHODS: We performed a secondary analysis with data from the PRESTO study, a multi-center prospective observational cohort study that included patients with suspected stroke. We used multivariable binary logistic regression analyses to assess the association with direct EMS notification and multivariable linear regression analyses to assess the association with the onset-to-alert time, onset-to-needle time and onset-to-groin time. RESULTS: Of 436 included patients, 208 patients (48%) contacted EMS directly. FAST scores (aOR 1.45 for every point increase, 95%CI: 1.14-1.86), alert outside office hours (aOR 1.64 [1.05-2.55]), and onset-to-alert time (aOR for every minute less [≤55 min]: 0.96 [0.95-0.97]) were independently associated with direct EMS notification. Direct EMS call was independently associated with shorter onset-to-alert times (27 min [54-0.84]) and with shorter onset-to-needle times (-30 min [-51 to -10]). The association between direct EMS call and the onset-to-groin time was almost similar to the association with onset-to-needle time, though not statistically significant (univariable analysis: 23.7 min decrease [-103.7 to 56.2]). CONCLUSION: More than half of all patients with suspected stroke do not call EMS directly but call their GP instead. Patients with higher FAST scores, alert outside office hours, and a rapid alert, more often call EMS directly. Patients who call EMS directly are treated with IVT 30 min faster than patients who call the GP first. TRIAL REGISTRATION NUMBER: Netherlands Trial Register: NL7387, (www.trialregister.nl).

Accuracy of CTA evaluations in daily clinical practice for large and medium vessel occlusion detection in suspected stroke patients.

INTRODUCTION: Early detection of large vessel occlusion (LVO) is essential to facilitate fast endovascular treatment. CT angiography (CTA) is used to detect LVO in suspected stroke patients. We aimed to assess the accuracy of CTA evaluations in daily clinical practice in a large cohort of suspected stroke patients. PATIENTS AND METHODS: We used data from the PRESTO study, a multicenter prospective observational cohort study that included suspected stroke patients between August 2018 and September 2019. Baseline CTAs were re-evaluated by an imaging core laboratory and compared to the local assessment. LVO was defined as an occlusion of the intracranial internal carotid artery, M1 segment, or basilar artery. Medium vessel occlusion (MeVO) was defined as an A1, A2, or M2 occlusion. We calculated the accuracy, sensitivity, and specificity to detect LVO and LVO+MeVO, using the core laboratory evaluation as reference standard. RESULTS: We included 656 patients. The core laboratory detected 89 LVOs and 74 MeVOs in 155 patients. Local observers missed 6 LVOs (7%) and 28 MeVOs (38%), of which 23 M2 occlusions. Accuracy of LVO detection was 99% (95% CI: 98-100%), sensitivity 93% (95% CI: 86-97%), and specificity 100% (95% CI: 99-100%). Accuracy of LVO+MeVO detection was 95% (95% CI: 93-96%), sensitivity 79% (95% CI: 72-85%), and specificity 99% (95% CI: 98-100%). DISCUSSION AND CONCLUSION: CTA evaluations in daily clinical practice are highly accurate and LVOs are adequately recognized. The detection of MeVOs seems more challenging. The evolving EVT possibilities emphasize the need to improve CTA evaluations in the acute setting.

Open Microvascular Thrombectomy for Acute Intracranial Large Vessel Occlusion: Microsurgery in the Endovascular Thrombectomy Era.

BACKGROUND: Open microsurgical thrombectomy for acute intracranial large vessel occlusion (LVO) has been the subject of dozens of case reports and series. However, no clear indications exist to define its role in the management of acute ischemic stroke. Our aim was to review all the available data on open microsurgical thrombectomy, for both spontaneous as well as iatrogenic intracranial vessel occlusion, in terms of indication and results. METHODS: Of the 390 articles screened, 33 were included after full text screening. RESULTS: A total of 232 patients were reported, of whom 208 received microsurgical thrombectomy and 24 received bypass for large vessel occlusion. Patients were divided into a historic cohort (before 2002) and a recent cohort (articles published after 2002). Patients from the historic cohort were younger: median age, 55 years (interquartile range, 34-57 years) versus 69 years (interquartile range, 63-75 years) in the recent cohort (P < 0.01). The procedure was successful more often in the recent cohort (65% of patients in the historic cohort vs. 98% of patients in the recent cohort) and more patients experienced neurologic improvement (56% of patients in the historic cohort vs. 69% in the recent cohort). CONCLUSIONS: In the era of endovascular thrombectomy, open microsurgical techniques might still play a role in highly selected patients. The reported patients show that microsurgical thrombectomy seems efficient and effective in improving patient outcome. Ideally, a multidisciplinary approach with vascular neurosurgeons trained and skilled in microvascular techniques is recommended.